effect of preoperative pupil size on quality of vision after wavefront-guided lasik

Conditions: Myopia

Summary: the purpose of this study is to evaluate whether the size of the pupil has an effect on quality of vision in patients undergoing lasik surgery.

purpose: to prospectively evaluate the effect of preoperative pupil size on quality of vision after wavefront-guided lasik. methods: fifty-one patients underwent lasik for low myopia and completed questionnaires regarding specific visual symptoms before and after surgery. each eye was evaluated postoperatively at 1-week, 1-, 3-, 6- and 12-months. pupils were stratified according to size: small (\ 6.0mm). mesopic pupil size and preoperative and postoperative variables were evaluated using analysis of variance (anova). a regression model was also performed to determine the correlation between mean spherical equivalent and cylinder and visual symptoms.

Eligibility criteria:
inclusion criteria: 1. no more than 6.00 d of spherical myopia 2. no more than 3.00 d of refractive astigmatism 3. a stable refraction (less than 0.50d per year of sphere or cylinder) 4. a corneal diameter of less than 11.0 mm to allow for suction ring fixation 5. discontinuation of soft contact wear at least 7 days prior to preoperative evaluation 6. visual acuity correctable to at least 20/20 7. age older than 21 years 8. ability to participate in follow-up examinations for 12 months after lasik surgery exclusion criteria: 1. use of rigid gas permeable contact lens 2. severe dry eye symptoms 3. severe blepharitis 4. anterior segment abnormalities (i.e. cataracts, corneal scarring, or neovascularization within 1 mm of intended ablation zone) 5. recurrent corneal erosion 6. severe basement membrane disease 7. progressive or unstable myopia or keratoconus 8. unstable corneal mires on central keratometry 9. corneal thickness in which lasik procedure would result in less than 250 microns of remaining posterior corneal thickness below the flap postoperatively 10. baseline standard manifest refraction of more than 0.75 d in sphere power 11. or a difference of greater than 0.50 d in cylinder power compared with baseline standard cycloplegic refraction 12. a baseline standard cycloplegic refraction differing more than 0.75 in sphere, 0.50 d in cylinder 13. have a different type of astigmatism (i.e. with-the-rule) when the cylinder is greater than 0.50d compared to baseline standard cycloplegic refraction 14. preoperative assessment of ocular topography and/or aberrations indicates that either eye is not suitable candidate for lasik vision correction procedure (i.e. forme fruste keratoconus 15. corneal warpage, or pellucid marginal degeneration) 16. previous intraocular or corneal surgery 17. history of herpes zoster or simplex keratitis 18. patients on systemic corticosteroid or immunosuppressive therapy 19. immunocompromised subjects or clinically significant atopic disease 20. connective tissue disease 21. diabetes 22. steroid responder 23. macular pathology 24. pregnant or lactating patients 25. patients with sensitivity to planned study concomitant medications 26. patients participating in another ophthalmic drug or device clinical trial